In-situ interlaminar growth of an azine-linked covalent organic framework in the Ti3C2TX membrane for molecule sieving with stable and high-efficiency performance

Two-dimensional (2D) MXene membranes have attracted significant attention for their high efficiency in molecule separation. In this study, an interlaminar in-situ growth strategy was employed to incorporate TpHz into the adjacent layer space between the Ti3C2Tx nanosheets of the 2D Ti3C2Tx membrane. In the typical synthesis process, due to the hydrophilic nature of Ti3C2Tx, the aqueous phase monomer diffuses through the Ti3C2Tx layers, reacts with the organic phase monomer in the top-surface and generate TpHz in-situ. Gradually, TpHz grows into the interlaminar space of the Ti3C2Tx nanosheets and the interior of the membrane. Owing to the charge transfer interaction existing between the TpHz and Ti3C2Tx nanosheets, the adjacent layer space between the Ti3C2Tx nanosheets is broadened without compromising the structural stability of the composite membranes. Accordingly, the TpHz/Ti3C2Tx composite membrane (TTCM) exhibit highly efficient molecule sieving properties and excellent structural stability, with a high pure water permeance of 986.5 L m- 2 h- 1 center dot bar- 1 and a rejection rate of over 95.0 % for anionic organic dyes. Additionally, the TpHz/Ti3C2Tx layer, with the thickness of only 160 nm, in the TTCM could withstand 80 h of water and solution flushing at a flow rate of 40 L min- 1 in crossflow filtration tests, maintaining stable solution permeance of 448 L m- 2 h- 1 center dot bar- 1 and rejection rates of 95.3 % demonstrating its high structural stability and potential for expanding industrial application in molecule sieving processes.